In the course of treating and preparing subterranean wells for production, a well packer is run into the well on a work string or production tubing. The purpose of the packer is to support production tubing and other completion equipment such as a screen or safety valve adjacent to a producing formation and to seal the annulus between the outside of the production tubing and the inside of the well casing to block movement of fluids through the annulus past the packer location. The packer is provided with slip anchor members having gripping surfaces which cooperate with complementary opposed wedging surfaces, whereby the slip anchor members are extendable radially into gripping engagement against the well casing bore in response to relative axial movement of the wedging surfaces. The packer also carries annular seal elements which expand radially into sealing engagement against the bore of the well casing in response to axial compression forces. Longitudinal movement of the packer components which set the anchor slips and the sealing elements may be produced either hydraulically or mechanically.